Burglar-alarm



(No Model.)

J. C. DE WITT.

BURGLAR. ALARM.

No. 597,578. Patented Jan. 18,1898.

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. shank of an ordinary wood-screw 2, the oppo- UNITED STATES PATENT JOHN C. DE WIT'I, OF CLEAR LAKE, WISCOXSIN.

BU RG LAR-ALARM.

SPECIFICATION forming part of Letters Patent No. 597,573, dated January 18, 1898.

Application filed November 28, 1896 To all whom it may concern:

Be it known that 1, JOHN C. DE WITT, a citizen or the United States, residing at Clear Lake, in the county of Polk and State of VVisconsin, have invented certain new and useful Improvements in Burglar-Alarms; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention has relation to improvements in portable or pocket burglar-alarms 3 and the object of the invention is to provide a simple, cheap, and reliable device of this class for the use of travelers and others.

To this end the novelty consists in the construction, combination, and arrangement of the several parts of the same; as will be hereinafter more fully described, and particularly pointed out in the claim.

In the accompanying drawings the same reference-numerals indicate the same parts of the invention.

Figure 1 is a perspective view ofmy improved burglar-alarm. Fig. 2 is a longitudinal section of the same ready for use. Fig. 3 is a similar view as it appears when closed or not in use, and Fig. 4 is a top plan view of the same as it appears applied to a door.

1 1 represent the parallel jaws, in one end of which is permanently fixed the projecting sitely-projecting end of which is formed into a solid nipple 3.

1 represents a U shaped spring secured be tween the jaws 1 1 by a rivet 5, the shorter end 6 of said spring being secured in place by lugs 7 7 on the inside of the jaws 1 1. The longer free end 8 of this spring engages a recess 9 in the hub 15 of the hammer 10, which is fulcrnmed on a rivet 12 between the jaws 1 1, and the outer end of this hammer terminates in a head 13, which is normally held in contact with the nipple 3 by the free end 8 of the spring exerting its tension on the toe 14 of the hammer 10. The hub 15 of the hammer is formed with an eccentric face 16, which rides under the free end of said spring when the hammer is swung out to set it, the spring exerting a tendency to close it until the hammer has been swung outwardly far enough for the free end of the spring to engage the plane face 17 of the hub 15,which holds the hammer in a state of rest when extended, as shown in Fig, 2.

. Serial to. 613,796. on model.)

By referring to Fig. 4 it will be seen that the alarm is secured to the door-frame by means of its screw and the hammer-arm opened, so that it projects into the path of the door when opened, the free end of the spring resting on the plane portion of the hub 17, which holds the said hammer-arm in this extended position. An ordinary fulmihating-cap is'then placed on the nipple 3, and the device is ready for use. If the door he now opened, it will strike against the free end of the hammer-arm and-move it sufficiently to release its plane face 17 from the spring, the tension of which is then exerted or transferred to the eccentricface 16 of the hub, which swings the hammer-arm around on its fulcrum-rivet 12, causing the head 13 to explode the cap on the nipple and thereby sound an alarm.

It will be noticed that when the spring is at rest its longer arm is free from its bend up to the hammer-hub, but when the hammer-arm is swung out or cooked the arm rests about midway of its length against the end of the shorter arm 6, which increases its tendency to retract.

Although I have specifically described the construction and relative arrangement of the several elements of my invention, I do not desire to be confined to the same, as such changes or modifications may be made as clearly fall within the scope of my invention without departing from the spirit thereof.

Having thus fully described my invention, what I claim as new and useful, and desire to secure by Letters Patent of the United States, is-

A pocket detonating burglar-alarm, comprising the integral parallel jaws 1 1, formed with the integral oppositely-disposed lugs 7 7, the rivet 5 connecting said parallel jaws, and the U-shaped spring at encompassing said rivet, and having its shorter end 6 engaging said lugs 7 7, in combination with the integral screw and nipple fixed in the closed end of said jaws, and the hammer-arm 10, pivoted in the free ends of said jaws, and in operative engagement with said hammer-arm, substantially as shown and described.

In testimony whereof I hereunto afliX my signature in presence of two witnesses.

JOHN C. DE WITT.

Witnesses:

MARIA SADLER, HATTIE FARGO. 

